The invention pertains to a rotatable cutting tool-tool holder assembly wherein the cutting tool rotates relative to the tool holder and the tool holder is attached to a driven member. More specifically, the invention pertains to a rotatable cutting tool-tool holder assembly wherein the cutting tool rotates relative to the tool holder (which is attached to a driven member) and the rotatable cutting tool experiences improved rotation, and thus longer tool life, as well as an enhanced ability to be removed from the tool holder.
Over the years rotatable cutting tools have been used for many types of applications in which the cutting tool is used to impinge a substrate (or earth strata). Typically, the rotatable cutting tool has a hard cemented carbide insert at the forward end thereof and is rotatably retained adjacent the rearward end thereof by a tool holder so that the cutting tool rotates relative to the tool holder. The tool holder is attached to a driven member such as, for example, a chain, a wheel, or a drum. Typical applications for rotatable cutting tools include coal mining, trenching, drilling, road planning, and other applications where the rotatable cutting tool is driven so as to impinge an earth strata (e.g., coal, the ground, asphalt pavement, asphaltic concrete, concrete, or the like). The earth strata is broken and fractured upon the impact caused by the impingement of the rotatable cutting tool thereon so as to generate debris. This debris comprises large pieces or chunks of earth strata, as well as smaller pieces of earth strata and even very fine particles including dust-like particles of earth strata. The debris is being propelled at great velocities in the vicinity of the cutting tool and the tool holder.
Because of the severe environment in which a rotatable cutting tool-tool holder assembly may often operate (e.g., a road planning application or a coal mining application), the cutting tool is subjected to great forces. These forces can quickly destroy (or render ineffective) the cutting tool if the cutting tool fails to effectively rotate. It thus becomes very apparent that it is important to the successful and efficient usage of a rotatable cutting tool-tool holder assembly that the cutting tool consistently rotate throughout its operation.
Heretofore, the infiltration of debris between the cutting tool and the tool holder, i.e., the contamination of the interface between the cutting tool and the tool holder, has resulted in the ineffective rotation of the cutting tool, or in some cases the complete failure of the cutting tool to rotate. The ineffective rotation, or complete rotational failure of the cutting tool generally results in the severe uneven wear of the hard insert, and possibly the eventual dislodgement of the hard insert from the cutting tool body. Either one of the above results essentially terminates the useful life of the cutting tool.
In the past there have been attempts to limit the passage of debris to the interface between the cutting tool and the tool holder. For example, U.S.
Pat. No. 4,603,911 to Hindmarsh et al. disclosed the of a thrust ring that was positioned within a special enlarged diameter section of the bore in the tool holder. The thrust ring had a V-shaped forward surface that registered with a complementary channel in the cutting tool. The structure disclosed by U.S. Pat. No. 4,603,911 used a number of components so as to be relatively complex. The complexity of the Hindmarsh et al. structure would be a disadvantage due to the severe environment in which these tools typically operate. Sandvik Rock Tools has apparently marketed a product under the designation SYSTEM 35 (Sandvik brochure entitled xe2x80x9cDrive Ahead with SYSTEM 35xe2x80x9d with an apparent date of 1987) which according to Sandvik was covered by U.S. Pat. No. 4,603,911.
During the 1980""s, Kennametal Inc. of Latrobe, Pa. 15650 introduced rotatable construction tools under the designations C3KLR and C3KBF that presented a somewhat enlarged diameter shoulder diameter. The C3KLR construction tool and the C3KBF construction tool each experienced somewhat improved rotational properties.
During the mid-1990""s, American Mine Tool of Chilhowie, Va. introduced a tool holder under the designation CB783. The CB783 tool holder presented a seat diameter that was about the same size as the shoulder diameter of the rotatable cutting tool. The use of the CB783 tool holder, especially when used in conjunction with a M3 rotatable cutting tool, resulted in some improvement in the rotational properties of the cutting tool. Although the above documents and products comprised attempts to improve the rotational properties of rotatable cutting tools, problems with the rotation of the cutting tools still existed due to the contamination of the interface between the cutting tool and the tool holder.
It thus becomes apparent that it would be desirable to provide a rotatable cutting tool-tool holder assembly that would help prevent the infiltration of debris between the cutting tool and the tool holder so as to promote the efficient rotation of the cutting tool during operation and increase the useful tool life of the cutting tool. It would also be desirable to provide a rotatable cutting tool itself that would prevent the infiltration of debris between the cutting tool and the tool body during operation and increase the useful life of the cutting tool.
The severe environment in which rotatable cutting tools may operate may also result in difficulties connected with the removal of the worn cutting tools from their respective tool holders. In the case of a road planning application, the cutting tools may be in hard-to-reach locations on the road planing drum. Difficult-to-remove cutting tools located in difficult-to-reach locations on a road planing drum are particularly troublesome for the operator to remove. The additional time and effort necessary to remove these worn cutting tools results to a reduction in overall efficiency of the road planing operation.
It thus becomes apparent that it would be desirable to provide a rotatable cutting tool-tool holder assembly that facilitates the removal of the worn cutting tools from their respective tool holders. It would also be desirable to provide a rotatable cutting tool itself that facilitates the removal of the cutting tool from the tool holder.
In one form thereof, the invention is an assembly of a rotatable cutting tool and a tool holder. The rotatable cutting tool includes an elongate tool body that has an axially forward end and an axially rearward end, a longitudinal axis, an integral head portion adjacent to the axially forward end, an integral shank portion adjacent to the axially rearward end, and an integral enlarged dimension portion mediate of the head portion and the shank portion. The enlarged dimension portion of the elongate tool body has a periphery and a rearwardly facing surface defining a generally planar shoulder. The elongate tool body has a hard insert at the axially forward end thereof. The tool holder comprises a tool holder body that contains a bore that has a forward end and a rearward end. The tool holder body defines an integral mating surface surrounding the forward end of the bore. The mating surface has a peripheral edge. The shoulder has a first transverse dimension, and the mating surface has a second transverse dimension. The first transverse dimension is greater than the second transverse dimension. The rotatable cutting tool is rotatably retained in the bore of the tool holder body so that the shoulder of the elongate cutting tool body contacts the mating surface of the tool holder body and the periphery of the enlarged dimension portion of the elongate cutting tool body extends radially outwardly past the peripheral edge of the mating surface.
In another form thereof the invention is a rotatable cutting tool for use with a tool holder. The tool holder includes a tool holder body that contains a bore that has a forward end and a rearward end wherein the tool holder body defines a mating surface with a peripheral edge and a transverse dimension. The mating surface surrounds the forward end of the bore. The cutting tool comprises an elongate tool body that has an axially forward end and an axially rearward end, a longitudinal axis, an integral head portion adjacent to the axially forward end, an integral shank portion adjacent to the axially rearward end, and an integral enlarged dimension portion mediate of the head portion and the shank portion. The enlarged dimension portion of the elongate tool body has a periphery and a rearwardly facing surface that defines a generally planar shoulder. The elongate tool body has a hard insert at the axially forward end thereof. The shoulder has a transverse dimension that is greater than the transverse dimension of the mating surface. The rotatable cutting tool is rotatably retained in the bore of the tool holder body so that the shoulder of the elongate cutting tool body contacts the mating surface of the tool holder body and the periphery of the enlarged dimension portion of the elongate cutting tool body extends radially outwardly past the peripheral edge of the mating surface.
In still another form thereof the invention is an assembly of a rotatable cutting tool and a tool holder. The rotatable cutting tool includes an elongate tool body that has an axially forward end and an axially rearward end, a longitudinal axis, an integral head portion adjacent to the axially forward end, an integral shank portion adjacent to the axially rearward end, and an integral enlarged dimension portion mediate of the head portion and the shank portion. The enlarged dimension portion of the elongate tool body has a periphery and a rearwardly facing surface that defines a generally planar shoulder. The elongate tool body has a hard insert at the axially forward end thereof. The tool holder comprises a tool holder body, which has a top surface, that contains a bore with a forward end and a rearward end. A boss extends from the top surface of the tool holder body so as to define the forward end of the bore. The boss has an integral mating surface that surrounds the forward end of the bore. The mating surface has a peripheral edge. The shoulder has a first transverse dimension and the integral mating surface has a second transverse dimension wherein the first transverse dimension is greater than the second transverse dimension. The rotatable cutting tool is rotatably retained in the bore of the tool holder body so that the shoulder of the elongate cutting tool body contacts the integral mating surface of the boss and the periphery of the enlarged dimension portion of the elongate cutting tool body extends radially outwardly past the peripheral edge of the integral mating surface.
In still another form thereof, the invention is an assembly assembly of a rotatable cutting tool and a tool holder. The rotatable cutting tool has an elongate tool body that includes a forward end and a rearward end, a longitudinal axis, an integral head portion adjacent to the forward end, an integral shank portion adjacent to the rearward end, and an integral enlarged dimension portion mediate of the head portion and the shank portion. The enlarged dimension portion of the tool body has a periphery and a rearwardly facing surface that defines a generally planar shoulder. A hard insert is at the forward end of the tool body. The tool holder comprises a tool holder body that contains a tool holder bore with a forward end and a rearward end. The tool holder further comprises an elongate sleeve that has a sleeve bore with a forward end and a rearward end. The sleeve has an integral mating surface that surrounds the forward end of the sleeve bore. The mating surface has a peripheral edge. The shoulder has a first transverse dimension and the mating surface has a second transverse dimension wherein the first dimension is greater than the second transverse dimension. The elongate sleeve is retained within the bore of the tool holder. The cutting tool is rotatably retained within the sleeve bore of the sleeve so that the shoulder of the cutting tool body contacts the mating surface and the periphery of the enlarged dimension portion of the cutting tool body extends radially outwardly past the peripheral edge of the mating surface.